Air Pollution: Sources, Effects, and Solutions

Posted on Jul 31, 2024 in Geology

AIR

Air is a set of gases that form the atmosphere, essential for life on our planet. It is a natural resource in constant exchange within the biosphere.

AIR POLLUTION

Air pollution refers to the contamination of the air and includes acoustic contamination. It involves the presence of materials or forms of energy in the air that pose risks, harm, or serious discomfort to people, goods, and the environment.

SOURCES OF POLLUTION

There are two main types of pollution sources:

  • Natural: These sources include activities within the geosphere and biosphere, as well as other natural processes.
  • Artificial: These sources are a result of human presence and activities.

AIR POLLUTANTS

Air pollutants are chemical substances and forms of energy that, in certain concentrations, can cause discomfort, risk damage to living organisms, or disrupt the functioning of ecosystems.

Residence Time

Residence time refers to the period pollutants remain in the atmosphere, either on their own or while participating in chemical reactions.

Primary Pollutants

Primary pollutants are substances with varied natural and chemical compositions that are directly emitted into the atmosphere from identifiable sources.

Secondary Pollutants

Secondary pollutants originate from primary pollutants through chemical reactions that take place in the atmosphere. These reactions form new pollutants or transform existing ones.

FORMS OF ENERGY

Ionizing Radiation

Ionizing radiation consists of particles or electromagnetic waves that can ionize atoms or molecules of matter. This radiation directly impacts chemical equilibrium, altering the structure and functions of matter. Examples include alpha, beta, X-rays, and gamma rays.

Non-Ionizing Radiation

Non-ionizing radiation consists of electromagnetic waves that do not change the structure of matter or cause ionization in atoms. Originating from the sun, examples include infrared, ultraviolet, and microwave radiation.

Noise Pollution

Noise is considered a special type of atmospheric pollution with a significant impact on populations.

DISPERSION OF POLLUTANTS

Emission Rate

Emission rate refers to the quantity of pollutants discharged from a source into the atmosphere over a given time period.

Susceptibility

Susceptibility refers to the quantity of pollutants present in a specific atmosphere after being transported, disseminated, or mixed. It represents the level of exposure for living organisms and materials under its influence.

Factors influencing the dispersion of pollutants include:

  • Characteristics of emissions
  • Atmospheric conditions
  • Topographical and geographical characteristics

Characteristics of Emissions

When the temperature of a gas is higher than its surroundings, it rises and disperses more easily.

Atmospheric Conditions

Atmospheric factors influencing dispersion include:

  • Air temperature and its variations with height
  • Winds
  • Precipitation (cleanses the atmosphere by dragging pollutants to the ground)
  • Sunlight (favors reactions among pollutants, potentially increasing their concentration)

Geography and Topography

Geographical location and relief influence the origin of breezes. The impact of this phenomenon varies across zones:

  • Coastal areas: Breeze systems during the day carry pollutants inland, while at night, they move towards the sea.
  • Areas of river valleys and hills: These areas experience valley breezes. During the day, slopes warm up, generating an upward current. Meanwhile, cold air accumulates at the bottom of the valley, creating a thermal inversion.

The Presence of Plant Masses

Vegetation reduces air pollution by slowing wind speed and absorbing carbon dioxide.

The Presence of Urban Centers

Urban centers influence air mass movement, decreasing their speed. They also exhibit the”heat islan” effect, where temperatures within the city are higher than in surrounding areas.

EFFECTS OF AIR POLLUTION

Air pollution alters the normal proportions of air components, causing negative effects on living organisms. Based on the radius of action, we can categorize these effects as local, regional, and global.

Types of Pollutants

Common air pollutants include particulates, sulfur compounds, and organic compounds.

Local Effects

Local effects include the formation of fog or smog. There are two main types:

  • A) Sulfurous smog: Originates from high concentrations of particulate matter and sulfur dioxide (SO2) in urban areas, often from cars and factories.
  • B) Photochemical smog: Results from the presence of atmospheric photochemical oxidants. This process is facilitated by anticyclonic situations, strong sunlight, and weak winds.

Photochemical Reactions

  1. Formation of ozone from the nitrogen dioxide photolytic cycle.
  2. Formation of free radicals from hydrocarbons, which oxidize nitric oxide (NO) to nitrogen dioxide (NO2).
  3. Formation of peroxyacetyl nitrate.

Regional Effects: Acid Rain

Acid rain occurs when sulfur and nitrogen compounds, released into the atmosphere through combustion processes, react, precipitate, and deposit on the Earth’s surface. This deposition can occur through dry or wet methods.

Effects of Acid Rain

  • Ecosystems: Acidification of rivers and lakes leads to the disappearance of aquatic species.
  • Soil: Increased acidity alters vegetation composition.
  • Materials: Corrosion of materials, particularly metals.

Global Effects

Global effects impact the entire planet. Examples include the hole in the ozone layer and climate change.

Role of NOx in Ozone Depletion

Stratospheric nitrogen oxides (NOx) act as catalysts in ozone destruction reactions, which can occur repeatedly. The ozone hole is more pronounced over the South Pole due to the presence of the Antarctic continent. During the intense cold of winter, a continental anticyclone forms, trapping cold air. In summer, ice crystals in clouds at higher latitudes release chlorine and bromine compounds that react with ozone, depleting it. The absence of NO2 in the atmosphere allows this reaction to proceed.

AIR QUALITY

Defining air quality is complex and often involves a set of rules and regulations with varying degrees of legislative enforcement.

Monitoring Air Quality

Monitoring systems and procedures are used to evaluate the presence of pollutants in the atmosphere.

  • A) Surveillance networks: Local, community, and global networks analyze and track data on greenhouse gases and the ozone layer.
  • B) Analysis methods: These include physical processes based on air samples subjected to tests and chemical methods based on the transformation of the substance under analysis.
  • C) Biological indicators: These methods analyze the sensitivity of certain species to specific gaseous pollutants.
  • D) Use of LIDAR sensors: LIDAR (Light Detection and Ranging) sensors can detect and measure pollutants in the atmosphere.

PREVENTION AND CORRECTION MEASURES

1. Preventive Measures

  • Land-use planning
  • Environmental impact assessments
  • Employment of low-emission technologies
  • R&D programs focused on pollution control
  • Improving fuel quality and types
  • Legislation and regulations

2. Corrective Measures

  • Concentration and retention of particles
  • Gas cleaning systems
  • Controlled expulsion of pollutants